Great stuff , I will have to try python for my graphs.
Once you get the hang of it, it isn't complicated. This is a very simple unadorned example that gets data from my minute data csv file and plots it:
import pandas as pd
import plotly.graph_objects as go
from plotly.subplots import make_subplots
df = pd.read_csv(r'Z:\modbus\mideadata.csv')
fig = make_subplots()
fig.add_trace(
go.Scatter(
x = df['datetime'],
y = df['LWT'],
line_color = "#0087A2",
name = 'LWT'
)
)
fig.add_trace(
go.Scatter(
x = df['datetime'],
y = df['RWT'],
line_color = "#FFC36E",
name = 'RWT'
)
)
fig.show()
It uses plotly graph_objects rather than plotly express (gives you a bit more flexibility), df is the dataframe, and df['LWT'] is a column in the dataframe. The datetime in the csv file is in the format '2023-03-21T11:58:18' and between them pandas and ploty work out that is a date time, and give this (which is interactive, I can zoom and pan etc) in my browser (I've zoomed in to the last three nights):
Midea 14kW (for now...) ASHP heating both building and DHW
The 2091 options, confusingly, actually allow the user to select from five options:
The user can use either the inbuilt Samsung Water Thermostat
OR
The User can use an external Thermostat transmitting it's state with a On/OFF Signal.
Warning , further confusion arises from the use of the term "External Thermostat" .
This External Thermostat is NOT the ROOM Thermostat.
Option 0 : Do NOT use either the external OR the internal Thermostats.
Option 1: Use the On/OFF Signal from the External Thermostat.
Option 2: Use the External Signal ON/OFF OR fire the thermostat when the Pipe Water Temperature equals that selected by the user on the Samsung Front Panel.
Use a Hysteresis value of 0 degrees meaning that a ON to OFF Thermostat Temperature transition is equal to the OFF to ON Transition.
This option is Designated as "Water Pump 1". Note not Pump 1 , application 1.
Option 3: Use the External Signal ON/OFF OR fire the thermostat when the Pipe Water Temperature equals that selected by the user on the Samsung Front Panel.
Use a Hysteresis value of 1 degree meaning that a ON to OFF Thermostat Temperature transition is one degree C greater than the OFF to ON Transition.
This option is Designated as "Water Pump 2".
Option 4: Use the External Signal ON/OFF OR fire the thermostat when the Pipe Water Temperature equals that selected by the user on the Samsung Front Panel.
Use a Hysteresis value of 1 degree meaning that a ON to OFF Temperature transition is one degree C greater than the OFF to ON Transition.
This option is Designated as "Water Pump 3".
Option 4 Cycle modification.
When the ON to OFF signal is generated by the Thermostat a delay timer of 3 minutes duration is started.
When the delay is completed the Water Motor is stopped for seven minutes.
With the completion of the seven minute motor stop the motor is started for three minutes.
During these three minutes the water temperature is increased , increasing the cycle time .
The motor is turned OFF for seven more minutes completing option 4.
Why use Hysteresis and mid-Cycle pulsing :
1) Hysteresis greatly reduces Thermostat misfiring in the presence of signal or thermal noise.
2) Mid- Cycle pulsing also reduces misfiring caused by noise and slightly increases the cycle time.
Sorry for the explanation . this is, however, not easy to explain with the use of conflicting numbers particularly confusing.
A first rate Technical Author would be required.
No Wonder the French Samsung Engineer could not understand this !
Option 0 : Do NOT use either the external OR the internal Thermostats.
This is incorrect. This setting allows you to use the thermostat in the wired controller and set up room temperature mode. The water law settings still apply, but you can control your heating by setting different room temperature targets for different times of the day via the weekly schedule facility. There are two examples on a different forum, where changing to room temperature mode made a huge difference to their short cycling. Since I changed to this mode, I haven't had any short cycling even with outside temperatures as high as 13C. The wired controller has to be in a suitable location for this to work, but moving it is not difficult.
If you haven't tried this mode, then I strongly recommend it, although I get the feeling that your unusual piping set up is not helping.
The Field option, 2092 is not used, being the control for an Second, unused, Zone.
The Field Option ,2092 uses the Graphical control Graph Water Law 2, WL2.
I have No second Zone.
Option 2093:
The Field option, 2093 is not used, being the control for an Third , unused, control in another Zone.
The Field Option ,2093 uses the Graphical control Graph Water Law 2, WL2.
Option 2091:
The Field option, 2091 is used, allowing, in my case, the operation of the Front panel Water Law ( Samsung Weather compensation) Offset Thermostat.
The Field Option ,2091 uses the Graphical control Graph Water Law 1, WL1.
The Water Law ( Samsung Weather Compensation ) Control Graphs ,
Option 201:
The Outside Temperatures , graphical ordinates, for Both Water Law 1 and Water Law 2 are set by Field bits 201.
Field bit 201 has two Sub fields , a Low outside Temperature and High Outside Temperature.
Confusingly, the Low Temperature is here the highest , outside Graphical coordinate value of 15 C.
Equally, confusingly , the High Temperature is the lowest value , being varied between -2 C ( England), -5 C ( South Scotland ) and -6 C ( North Scotland).
I have used , and varied the High setting between -4 and -6C as directed by the Samsung Manuals , You tube videos and talks with "experts".
Option 202:
The Field bit 202 has two Sub Fields setting the graphical co-ordinates for Water Law 1 Only.
The Water Temperature has here , Two Coordinates.
1): The required Water Temperature when the Outside Temperature is High , varied between +30 and +35C.
2): The required Water Temperature when the Outside Temperature is Low ( -3,-5 or -6 C) , varied between +40 and +50 C.
The Temperature Water Law 1 ( Samsung Weather Compensation ) with Offset is shown on the following:
Where the Water Temperature was set to +30 C when the outside Temperature was +15 C.
The Water Temperature was set to +45 C when the Outside Temperature was - 5 C.
Option 203:
The Temperature Water Law 2 ( Samsung Weather Compensation on Zone 2) with Offset is shown on the following:
Where the Water Temperature was set to +30 C when the outside Temperature was +15 C or greater.
The Water Temperature was set to +40 C when the Outside Temperature was - 5 C or lower.
Definitely thought up by someone with a passion for Y=mX + C , "O Level Maths".
I used 2091 , "not used " between Aug 2022 until Nov 2022.
In case I made a mistake, I have just now set the 2091 to "Not Used".
As, before, the Front panel Water Law Display has vanished .
I have No Water Law , Samsung Weather Compensation.
My experience with option 2091 "Not Used" is that my Heat Pump becomes even more inefficient while the " Short Cycling " remains.
Very heavy "Short Cycling " has been apparent whither I use Weather compensation or Not.
Now ,my Weather compensation has completely stopped.
I did consider moving the wired controller into my living room , but, abandoned the idea with the increased inefficiency resulting from the loss of Weather Compensation and the loss of Room Thermostat control of my Living room Temperatures.
I know I can operated using the wired controller , 2091 " not used" using the scheduler , but that is inconvenient to say the least.
You should see Set indoor and this is adjustable. However weather compensation still operates just as it did when using an external stat. The ONLY difference is the inability to change the offset.
I set my LWT sufficiently high so that the ASHP runs for an hour or so and is then switched off by the stat. The COP is lower, but electricity usage is also lower and no cycling.
If you use room temperature mode, you may need to set 2093 to 1 to minimise cycling, as recommended by someone in the other forum, although mine is still set on 2.
The Field option, 2092 is not used, being the control for an Second, unused, Zone.
The Field Option ,2092 uses the Graphical control Graph Water Law 2, WL2.
I have No second Zone.
Option 2093:
The Field option, 2093 is not used, being the control for an Third , unused, control in another Zone.
The Field Option ,2093 uses the Graphical control Graph Water Law 2, WL2.
Option 2091:
The Field option, 2091 is used, allowing, in my case, the operation of the Front panel Water Law ( Samsung Weather compensation) Offset Thermostat.
The Field Option ,2091 uses the Graphical control Graph Water Law 1, WL1.
The Water Law ( Samsung Weather Compensation ) Control Graphs ,
Option 201:
The Outside Temperatures , graphical ordinates, for Both Water Law 1 and Water Law 2 are set by Field bits 201.
Field bit 201 has two Sub fields , a Low outside Temperature and High Outside Temperature.
Confusingly, the Low Temperature is here the highest , outside Graphical coordinate value of 15 C.
Equally, confusingly , the High Temperature is the lowest value , being varied between -2 C ( England), -5 C ( South Scotland ) and -6 C ( North Scotland).
I have used , and varied the High setting between -4 and -6C as directed by the Samsung Manuals , You tube videos and talks with "experts".
Option 202:
The Field bit 202 has two Sub Fields setting the graphical co-ordinates for Water Law 1 Only.
The Water Temperature has here , Two Coordinates.
1): The required Water Temperature when the Outside Temperature is High , varied between +30 and +35C.
2): The required Water Temperature when the Outside Temperature is Low ( -3,-5 or -6 C) , varied between +40 and +50 C.
The Temperature Water Law 1 ( Samsung Weather Compensation ) with Offset is shown on the following:
Where the Water Temperature was set to +30 C when the outside Temperature was +15 C.
The Water Temperature was set to +45 C when the Outside Temperature was - 5 C.
Option 203:
The Temperature Water Law 2 ( Samsung Weather Compensation on Zone 2) with Offset is shown on the following:
Where the Water Temperature was set to +30 C when the outside Temperature was +15 C or greater.
The Water Temperature was set to +40 C when the Outside Temperature was - 5 C or lower.
Definitely thought up by someone with a passion for Y=mX + C , "O Level Maths".
ian
You are once more not answering the questions I have asked, but instead providing a description of which I am fully aware.
Until you are prepared to actually answer my questions there is no further help that I can provide.
My Heat Pump has Two independent Water circuits performing Two different and independent operations.
1) Primary Water Loop.
The Primary Water loop controls the pipe Water temperature using a Temperature sensor inside my Heat Pump.
The Temperatures from the sensor are compared to the temperatures set by the Water Law Graph.
This Water Law control is selected by bits 2091 options " Water Pump 1" , "Water Pump 2" or "Water Pump 3".
This water loop has it's own motor , thermostat and outdoor Sensor.
The purpose is to independently control the Water Temperature as a function of the outdoor Temperature using a continuously varying "Inverter".
2) Secondary Water Loop.
The Secondary Water Loop controls the Room Temperature using a standard room Temperature Thermostat.
The Room Thermostat controls a second motor using ON/OFF Signals.
Practice
Using 2091 options " Water Pump 1" , "Water Pump 2" or "Water Pump 3" my Heat Pump works , and displays the results of the correct operation of a Weather Compensated System.
The Primary Water loop , however, generates extensive "Short Cycling" caused by the Primary loop water volume of 6 litres.
Question?
How many people have, like myself, a Two Water Circuit separated by a Heat Exchanger?
How many people are using these heat pumps without a Water Compensation Display?
Have I misunderstood your description of the operation of a Weather Compensated system without a display?
This water loop has it's own motor , thermostat and outdoor Sensor.
The purpose is to independently control the Water Temperature as a function of the outdoor Temperature using a continuously varying "Inverter".
You have what is sometimes referred to as flow separation. In your case this is done using a heat exchanger and in most other Samsung systems that I know of, this is done using a 4 pipe buffer tank. Your system is therefore not that different to those with buffer tanks. Also, there are several members of this forum who have heat exchangers like yours, albeit with different ASHP manufacturers and short cycling has not been a feature as far as I am aware.
The usual explanation for short cycling is that at lower flow temperatures, the emitters in the house emit less heat than the minimum that the heat pump can modulate down to. Glyn Hudson has a 5kW Samsung like you and feels that it can only modulate down to around 3kW. So if your emitters can only emit 2.8 kW at a flow temperature of say 32C, then the flow temperature leaving the ASHP (LWT) will rise above its set point and the compressor will stop. Depending on your 2091/2 settings, the water pump will run for 1 minute, 3 minutes or continue. When the LWT falls approx 2C below its set point the compressor will start up again. Several Samsung owners have described repeated cycles of around 8 minutes duration in this scenario (me included).
What emitters do you have and what is your calculated heat loss at your design temperature? At what LWT and outside air temperature (OAT) does your compressor short cycle? The problem with some buffer tanks and some heat exchangers is that the flow temperature to the emitters is often a few degrees less than the LWT from the ASHP. Therefore the emitters see a reduced temperature and emit less heat as a result, increasing the chances of short cycling.
How many people are using these heat pumps without a Water Compensation Display?
Have I misunderstood your description of the operation of a Weather Compensated system without a display?
I think you have misunderstood. Samsung uses Weather compensation by default. There are 2 main displays - one where you can adjust the LWT by increasing the offset by +/- 5C and the other where you adjust the desired minimum room temperature. Weather compensation is running whichever display is visible. When the offset display is used, an external thermostat is usually used to switch the ASHP on and off depending on set temperatures. When the room temperature set point is displayed, the thermostat in the wired remote controller will switch the ASHP on and off depending on set temperatures. The LWT will be controlled by the weather compensation settings, whatever display is chosen. All that the wired remote controller thermostat or the external thermostat does is switch the ASHP on or off. They do not control LWT.
The fact that your primary loop contains only 6 litres is neither here nor there as far as short cycling is concerned. It is the lack of heat emitted from the secondary loop that causes short cycling.
By the way, when I talk about short cycling, I am referring to the compressor, not any of the water pumps. In your previous posts, it has not always been clear whether you were referring to water pumps cycling instead.
I am increasingly depressed with contradictory , and often arrogant "advice" from the "Experts".
Samsung Minimum Modulation power.
I too have discovered that my Samsung Minimum Modulation is about 3 Kw.
With No Modulation below a power of 3 Kw, my Heat pump indeed starts "Short Cycling".
The "Short Cycling " was , originally ,18 months ago, indeed 8 minutes, confirming your explanation.
Weather Compensation
I used the Water Offset Display/Control under the mistaken belief that savings of between 7% to 10 % could be achieved.
I stand corrected, in not appreciating that Weather compensation was still used even when the Water Temperature Offset Display was NOT.
Winter freezing and Buffer Tanks
Samsung-Dallium advised that a Buffer tank should be installed on my system " to prevent winter freezing ".
The Samsung controller dumps water from the Buffer tank during cold winter nights without consuming Electricity.
My Buffer tank successfully and verifiably protects against Winter freezing.
"Short Cycling" ,Water volume and Buffer tanks.
The MCS produced the following statement about the severity of "Short Cycling".
I may be mistaken , but my understanding is that the "Cycle time " is a function of the Water Volume contained in the Water pipes connecting the Heat Pump to my Heat Exchanger.
Samsung also say that " Samsung Heat Pumps Do not "normally" require a Buffer tank, however, if the volume is less than 20 L a Buffer tank will be required.
Notice that Samsung , and the MCS, advise limiting, but not eliminating "Short Cycling".
Note that Both Samsung, Kendra and the MCS warn of the potential increase in losses from a buffer or Volumising tank.
Again, many thanks for your help in restoring some confidence, and lifting my depression .
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